Achieves 15.8/20.8 mpg city/highway.The 2016 Nissan Titan XD is an all-new model in the Japanese automaker's full-size pickup lineup. In our Real MPG testing, the new Titan XD with the available Cummins turbodiesel engine returned 20.8 mpg combined driving. With a gross vehicle weight rating (GVRW) up to 8,500 pounds, the Titan XD earns an exempt status from the EPA for fuel economy ratings. With that said, these numbers should give owners an idea of what kind of mpg numbers they can expect.